Electrical universal connecting box

ABSTRACT

For application to different standard dimensions of wires, cables or tubes an electrical connecting box is designed with a lower part (1) with a bottom (2) and upright side walls (6) therefrom, and an upper part (8) in the form of a cover having side walls for arrangement against a circumferential shoulder portion (11) on the side walls of the lower part (1). In the side walls (6) of the lower part one or more sets (16) of parallel punch lines (17-20) are formed extending from the bottom onto the shoulder portion (11) of the side wall. In the adjoining side wall the upper part (8) is formed with punch lines (21-23) shaped substantially as circular arcs so that in the assembled condition of the box blank portions of different sizes may be punched out to be adapted to individual wire, cable or tube dimensions. By designing also the upper part with blank portions limited by punch lines (29-31) and adapted to standard designs of electrical light dimmers, interruptors and/or plug-in switches, on one hand, and the passage of wires for lamp suspensions or the like, on the other hand the box may, in addition, be used as a switch casing or a ceiling box for lamp suspensions.

The invention relates to an electrical connecting box for low voltageinstallations comprising a lower part having a bottom to be arrangedagainst a fixed support and an upper part adapted for securing to thelower part, said upper part having side walls in at least one of which anumber af punch-out blank portions for providing openings for electricalinsulation tubes, wires and/or cables are defined by a set of punchlines, one of which forms a common border for the blank portions at oneside thereof.

In most known electrical connecting boxes the size of the punch-outblank portions is usually adapted to a single cable dimension, i.e. themaximum cable dimension for which the box in question is intended.Therefore, when using the blank portions for smaller cable dimensionsspecially designed plugs or bushings will have to be used in such boxes,said plugs or bushings fitting externally into the size of the blankportion and having a through-bore adapted to the desired cabledimension.

In addition to making installation works more expensive, the need forthe electrician to hold a storage of a greater selection of boxes andaccessories and to take such a selection with him to a given site ofinstallation is a disadvantage is practice.

However, from Norwegian Pat. No. 61678 and German Pat. No. 611474installation boxes are known, in which the side walls of the housinghave blank portions for different wire, cable and tube dimensionsdefined by a set of punch lines which in the embodiment according to theformer publication coincide and form a common border for all the blankportions at one side thereof.

Relative to these prior art designs, in which a set of blank portionsare provided in one and the same wall portion of a lid or a cover forthe box so that the number of wire dimensions which may be introducedinto the box will be limited to the number of blank portions in saidset, e.g. three, it is the object of the invention to obtain a furtherimproved flexibility with respect to the number of types of wires,cables and insulation tubes which without any difficulty may beintroduced into the box through blank portions and, thereby, furtherincrease the universal applicability of the box to all practicallyavailable standard dimensions of insulation tubes, cables and wires offlat and round cross section.

According to the invention such a universal box is characterized in thatthe lower part has upright side walls on all sides, said side wallshaving a circumferential shoulder part forming an abutment for edges ofthe side walls of the upper part, each set of punch lines comprising inthe side walls of the upper part a number of punch lines formedsubstantially as circular arcs and extending to said edges, each ofthese set of punch lines having a corresponding set of punch lines inthe adjoining side wall of the lower part, said latter punch lines beingparallel straight lines at right angles to the bottom of the lower part.

With this design blank portions may be punched out in said adjoiningside walls of the lower and upper parts adapted to individual cabledimensions with a safe location and without using special accessories.The proportioning of the side wall of the lower part and the set ofpunch lines therein may advantageously be such that the part of the sidewall of the lower part located between the bottom and thecircumferential shoulder part suits the smallest cable dimension forwhich the box is intended, such as flexible wires or flat cables so thatthese may be introduced without removing any blank portion from the sidewall of the upper part.

In preferred embodiments of the invention the universal applicability ofthe box is further improved for use not only as a wiring box, but alsoas a switch casing and/or lamp connection box in that additional punchlines are formed in the upper part for defining blank portions adaptedto one or more standard designs of electrical interruptors and/orplug-in switches and/or to the passage of wires for lamp suspensions orthe like. Thereby, one and the same box may be used both as a connectingbox and a switch box.

In the following the invention will be further explained with referenceto the drawings, in which

FIGS. 1 and 2 are perspective views of the lower part with associatedcable tension relieving devices and the upper part, respectively, of anembodiment of the connecting box according to the invention;

FIG. 3 shows a section of a side wall viewed from the interior of thebox;

FIGS. 4 and 5 are perspective views of locking devices for securing theupper part to the lower part; and

FIGS. 6 to 8 show a wire tension relieving device.

As shown in FIGS. 1 and 2 a connecting box according to the inventionmay be substantially box-shaped, the box comprising a lower part 1 witha bottom 2 in which screw holes 3 may be formed for mounting the box toa fixed support and with side walls 4 to 7 projecting upright from thebottom 2 as well as an upper part 8 designed as a lid having side walls9 to 12.

The side walls 9 to 12 of the upper part 8 cover a part of the sidewalls 4 to 7 of the lower part 1, said latter side walls being formedwith a circumferential shoulder portion 13 as an abutment for the edgeof the side walls 9 to 12 of the upper part 8.

In addition to the screw holes 3 the bottom 2 of the lower part 1 isformed with two circular blank portions 14 and 15 defined by punchlines, by the punching-out of which openings are formed for theintroduction of electrical insulation tubes having the standarddimension 5/8 inches.

In the embodiment shown there are formed in each of the side walls 4 and6 of the lower part two sets and in each of the side walls 5 and 7 oneset of parallel straight punch lines as shown at 16 for one of the punchline sets in the side wall 6. As shown in FIG. 5 the punch lines ofthese sets extend from the bottom 2 at right angles to the shoulderportion 11 of the side wall, and each set comprises four parallel punchlines 17 to 20, one of which 17 is disposed at a distance from the threeremaining ones 18 to 20, which have approximately the same mutualseparation. As further shown in FIG. 3 the wall thickness of the sidewall has been reduced at the punch line set 16.

As most clearly shown in the view in FIG. 3 of a section of a side wallwith the lower part 1 and the upper part 8 removed from each other asseen from the interior there is formed for each punch line set in theside walls 4 to 7 of the lower part 1 a set of punch lines 21 to 23,formed substantially as circular arcs, in the adjoining side wall of theupper part. These punch lines 21 to 23 extend to the edge of the sidewall of the upper part, in one side opposite the punch line 17 and inthe other side opposite each of the punch lines 18, 19 and 20 of thepunch line set 16 in the side wall of the lower part 1. Thus, at theedge of the side wall of the upper part the punch line 21 in the upperpart ends opposite the punch lines 17 and 18, the punch line 22 oppositethe punch lines 17 and 19 and the punch line 23 opposite the punch lines17 and 20.

Thereby, each punch line set will provide the possibility ofpunching-out blank portions corresponding to individual standarddimensions of cables, wires or tubes. Thus, when punching-out, e.g. ablank portion in the side wall of the lower part 1 between the punchlines 17 and 18 and corresponding punching-out of the blank portion inthe side wall of the upper part limited by the punch line 21, an openingadapted to the cross section of standard cables having two to fourconductors is provided when arranging the upper part 8 on the lowerpart 1. When punching-out a blank portion in the lower part between thepunch lines 17 and 19 an opening is provided which, when arranging theupper part without punching-out blank portion therein, is adapted to thecross section of a standard flat cable, whereas by punching-out the sameblank portion in the lower part and simultaneous punching-out of theblank portion in the upper part limited by the punch line 22 an openingis provided adapted to a standard five conductor cable of circular crosssection. When punching-out a blank portion between the punch lines 18and 20 or possibly 19 and 20 openings are provided in a correspondingmanner adapted to thinner flexible wires of different diameter. Finally,when punching-out blank portions limited by the punch lines 17 and 20 ofthe lower part and the punch line 23 in the upper part an opening isprovided adapted to the cross section of a standard insulation tubehaving a diameter of 5/8 inches.

As shown in FIG. 3, each of the punch lines 17 to 20 in the side wallsof the lower part and the punch lines 21 and 23 in the side walls of theupper part has the shape of a nick-like depression to a reduction of thewall thickness of about 75%.

In the embodiment shown the upper part 8 is fastened to the lower part 1by means of snap-locking devices, upright elastically deformable pins 24having locking projections 25 being provided at the two opposite sidewalls 5 and 7 of the lower part 1 as shown in FIGS. 4 and 5 forengagement with cut-outs 26 in the opposite side wall of the upper part8. Thereby, the upper part 8 may be lifted off from the lower part 1 asshown in FIG. 5 by depressing the locking projection 25 formed as a noseportion by means of a simple hand tool such as a screwdriver 27. Withthe illustrated form of the nose portion 25 with an obliquely cut upperside the upper part 8 will simultaneously be automatically lifted offfrom the lower part 1 by this release of the locking engagement.

In the embodiment shown the field of application of the box according tothe invention is further enlarged so that the box may, in addition, beused as a switch casing and/or as a ceiling box for a lamp suspension inthat the upper part 8 is formed with punch lines 29-30 and 31 as shownin FIG. 2 for defining blank portions adapted to standard designs forelectrical light dimmers, interruptors and plug-in switches, on onehand, and to the passage of wires for lamp suspensions, on the otherhand. Thus, by punching-out only the square blank portion limited by thepunch line 29 a light dimmer or a standard interruptor may be mounted inthe upper part 8, and by punching-out this blank portion as well as theadjoining rectangular blank portion limited by the punch line 30 acorresponding plug-in switch may be mounted in the upper part.

For the arrangement of such standard interruptors or plug-in switchesthe lower part 1 is formed at shown in FIG. 1 with fastening devices inform of catching members 32, on one hand, for fastening interruptors orswitches of the kind having elastically biased catching members on thepart to be inserted into a switch casing or in the form of projections33, on the other hand, having pre-drilled holes for fastening screws forinterruptors or light dimmers.

For the purpose of relieving the tension of inserted flexible wires ofdifferent size in the box according to the invention the bottom 2 of thelower part 1 may be formed as shown in FIG. 1 with two sets ofprojecting ribs 35 having cut-outs 36 for fastening such different wiredimensions by means of tension relieving fittings 37 which is clampedfirmly by screwing screws into screw holes 38.

As further illustrated in FIG. 1 different wire sizes may be fastened byone and the same tension relieving fitting 37 of a special designcomprising two screw holes 38a extending between a flat side 39 and anopposite side having a projecting central portion 40 between the screwholes 38a. By using the flat side 39 for engagement against a wire arelatively great wire dimension may be fastened by means of the fitting37. By turning the fitting so as to use the projecting central portion40 for engagement against the wire, a wire of a smaller cross sectionmay be fastened by means of the same tension relieving fitting 37.

In a corresponding manner, wires of lamp suspensions may be relieved oftheir tension by means of a tension relieving device 41, shown in FIG.1, said device having screw holes 42 and such a length as to bemountable in the lower part by means of screw holes in each of the twosets of projecting ribs 35. The device 41 is designed as a commontension relieving means for a number of lamp suspension wirescorresponding to the number of blank portions in the cover 8 for thepassage of such wires. For this purpose the device 41 is provided asshown in FIGS. 6 to 8 with a number of aligned wire ducts 43 between thescrew holes and in parallel relationship thereto, in the embodimentshown seven such ducts, between which partitions 44 are provided whichin the mounted position of the tension relieving device 41 terminate ata distance from the bottom 2. Moreover, the side walls of the tensionrelieving device 41 are formed with cut-outs 45 opposite each wire duct43, said cut-outs being open towards the bottom 2.

As shown in FIG. 6 the screw holes 42 of the tension relieving device 41are displaced to either side of the central plane through the wire ducts43 and, moreover, in alignment with the screw holes 42 the device isformed with end guide member 46 for engagement with upright guide rails47 in the lower part of the box, so that it can be retained accuratelyin its position with respect to the blank portions in the upper part 8and with a good safety against capsizing and for reliable wire fasteningagainst rib-shaped projections 9 on the bottom 2 of the lower part 1.

I claim:
 1. An electrical connecting box for low voltage installationscomprising a lower part (1) having a bottom (2) to be arranged against afixed support and an upper part (8) adapted for securing to the lowerpart (1), said upper part having side walls (9-12) in at least one ofwhich a number of punch-out blank portions for providing openings forelectrical insulation tubes, wires and/or cables are defined by a set ofpunch lines (21-23), one of which forms a common border for the blankportions at one side thereof, characterized in that the lower part (1)has upright side walls (4-7) on all sides, said side walls having acircumferential shoulder part (11) forming an abutment for edges of theside walls (9-12) of the upper part (8), each set of punch linescomprising in the side walls (9-12) of the upper part (8) a number ofpunch lines formed substantially as circular arcs and extending to saidedges, each of these set of punch lines having a corresponding set ofpunch lines (16) in the adjoining side wall of the lower part, saidlatter punch lines (17-20) being parallel straight lines at right anglesto the bottom (2) of the lower part (1).
 2. An electrical connecting boxas claimed in claim 1, characterized in that additional punch lines (29,30) are formed in the upper part (8) for defining punch-out blankportions adapted for one or more standard designs or electrical lightdimmers, interrupters and/or plug-in switches, means (32-34) beingprovided in the lower part for holding such standard designs.
 3. Anelectrical connecting box as claimed in claim 1 or 2, characterized inthat additional punch lines (31) are formed in the upper part (8) fordefining blank portions adapted for the passage of wires for lampsuspensions or the like.
 4. An electrical connecting box as claimed inclaim 1 or 2, characterized in that the lower part (1) is provided withupright elastically deformable pins (24) having locking projections (25)for engagement with cutouts (26) in the side walls (10, 12) of the upperpart (8).
 5. An electrical connecting box as claimed in claim 4,characterized in that said locking projections (25 are formed as noseportions having obliquely cut upper sides (28).
 6. An electricalconnecting box as claimed in claim 1 or 2, characterized in that thebottom (2) is provided with upright ribs (35) having screw holes (38)for tension relieving fittings (37) for fastening various wiredimensions.
 7. An electrical connecting box as claimed in claim 6,characterized by a tension relieving fitting (37) common to severaldimensions having two screw holes (38a) extending between a flat side(39) and an opposite side with a projecting central portion (40) betweenthe screw holes (38a).
 8. An electrical connecting box as claimed inclaim 6, characterized by an elongate tension relieving device (41)cooperating with said blank portions for wires for lamp suspensions andhaving two screw holes (42) and a number of aligned wire ducts (43)between the screw holes (42) and in parallel relationship thereto withpartitions (44), which in the mounted condition of the tension relievingdevice terminate at a distance from the bottom (2) of the lower part(1), at least one side wall of the tension relieving fitting (41) beingformed with cut-outs (45) opposite each wire duct (43) and openingtowards the bottom of the box.